Slice meat very thin, then cut slices into small chunks, about ½" squares. This is much easier to do if the meat is still slightly frozen.
Combine all other ingredients in a medium bowl. Add meat to marinade. Refrigerate for 2+ hours.
When ready to cook, heat a medium skillet over medium-high heat. Add meat to skillet. Cook until meat is browned. Continue to cook until the sauce reduces a bit. Keep warm until ready to serve.
Pickled Vegetables
Combine water, vinegar, sugar, and salt in a medium saucepan. Heat until boiling and sugar and salt have dissolved.
Place julienned vegetables into separate glass containers. Add 1 cup of vinegar mixture to each container. Refrigerate for 2+ hours, then pour the vinegar mixture out. This will leave the vegetables "lightly pickled." Refrigerate until ready to serve. These won't keep in the fridge as well as other pickles so make sure to use them within a few days.
Spinach
Combine all ingredients except spinach and avocado oil in a small bowl.
Heat oil over medium heat in medium skillet. Add spinach and cook 1-2 minutes, stirring frequently. Remove from heat and stir in soy sauce mixture.
Eggs
Cook eggs just before assembly. Make sure bowls are completely assembled before the eggs are cooked so you can add the eggs as the last component. Melt butter in a medium skillet. Keep the heat around medium-low. Gently crack eggs into the pan. Cook until whites are mostly set, about 3-4 minutes for sunny side up eggs. You can also flip the eggs after 2 minutes, then cook an additional 30 seconds - 1 minute for over easy eggs.
Rice
Heat oil over medium high heat in a large skillet or dutch oven/coated cast iron pan. Add cooked rice to pan and cook until crispy on the bottom, about 5 minutes.
Assembly
Spread rice on bottom of bowl. Top with meat. Arrange pickled vegetables, kimchi, spinach, and bean sprouts around the rice and meat. Top with fried egg and serve gochujang on the side.